Heat exchange apparatus



Dec. 15, 1959 J. D. CHRISTIAN 2,917,284

HEAT EXCHANGE APPARATUS Filed layA, 1956 v 4 Sheets-Sheet 1- I mm I i II I2 I .56 44 INVENTOR. I J Joseph 0. Chrfsfian ECKHOFF a! sL IKATTORNEYS BYAM /l- W A MEMBER F T 15 FIR s an 2 n M t mm, 5 2 a mfi flwp mm fiF F W. a w w 2 u n E h 0/ B S ed M 5E E 4 .w M A Y S E w N mm amm cm .C m

Dec. 15, 1959 Filed May 4, 1956 Dec. 151959 J. D. CHRISTIAN 7 2,917,284

. HEAT EXCHANGE APPARATUS Filedllay 4, 1956 4 Sheets-Sheet s INVENTORLJoseph D. Chr/sf/an ECKHOFF .S'VLICK 4 Sheets-Sheet 4 INVENTOR. JosephD. Chrisfian ECKHOFF 4 SLICK 47'7'ORNEY5' A MEMBER OF THE FIRM J. D.CHRISTIAN HEAT EXCHANGE APPARATUS Dec. 15, 1959 Filed May 4. 1956 UnitedStates Patent HEAT EXCHANGE APPARATUS Joseph D. Christian, SanFrancisco, Calif.

Application May 4, 1956, Serial No. 582,742

2 Claims. (Cl. 257-112) This invention relates to heat exchange andparticularly to a novel form of apparatus which can be utilized toimpart to or remove heat from a material, to the end that thetemperature of the material is desirably altered. The apparatus is alsocapable of other uses and some of these will be related in furtherdetail.

It is in general the broad object of the present invention to provide anovel form of device for controllably altering the temperature of amaterial.

Another object of the present invention is to provide an apparatus forcooling cement.

An additional object of the present invention is to provide a novelapparatus for the handling of meat scraps for production of tallow.

The invention includes other objects and features of advantage, some ofwhich, together with the foregoing, will appear hereinafter wherein thepresent preferred embodiment of the invention is disclosed. In thedrawings accompanying and forming a part hereof, Figure 1 is a sideelevation, partly in section, taken through a form of the apparatusembodying the invention and which is particularly suited to the coolingof cement.

Figure 2 is a section taken along the line 2-2 in Figure 1, and showingthe construction of the apparatus.

Figure 3 is a side elevation, partly in section, of an apparatusparticularly suited to the handling of tallow and the like.

Figure 4 is a top view of a portion of the apparatus shown in Figure 3.

Figure 5 is a section taken along the line 55 in Figure 3. v

Figure 6 is a side elevation, partly in section, of the apparatus shownin Figure 3.

Referring to Figure 2, the apparatus there shown includes four spacedvertical columns 11, extending upwardly from a suitable base 12, andproviding a support for a casing structure, generally indicated at 13.The casing structure includes a central vertical tube 14 about which areclustered four pairs of intermeshing vertical screws or helical bladedrotors 16 and 17. Each rotor includes a relatively large diameter hollowcentral shaft 18 having relatively narrow helical fins fastened thereto,the rotor shafts being supported in bearings 19 and 21 provided,respectively, at the bottom and the top of the casing. The helical finsin each pair preferably have the periphery of one closely approachingbut not in Wiping contact with the shaft of the other.

Each screw pair is closely confined within an arcuate housing made up ofan inner arcuate portion 22 and an outer cover portion 23. Each of theportions are flanged along their peripheral edges, as indicated at 24,the flanges being secured together by bolts 26. Each of the covers 23includes an opening 27, over which is mounted a movable door 28 topermit of regulation and control of recirculation of material, as willbe described. Also mounted over each cover is an outer cover 31, flangedas at 32 and secured by the bolts 26 in position over the cover 23. Theouter cover 31 is hollow to permit of fluid "ice circulation. It is tobe noted that the width of the inner arcuate portion between itsprojecting sidewalls is such that by removing the cover portion, thescrews are totally exposed. Further, this enables the screws to beremoved for inspection, testing and repair.

Stay bars 36 and 37 extend from the tube 14; stay bars 36 pass to eachof columns 11 through arcuate braces 38, which join adjacent pairs ofhousing members 22; stay bolts 37 extend between tube 14 and each of thehousing members 22.

Suitable gearing, generally indicated at 41, is mounted upon each of therotor shafts to permit of their drive from the prime mover 42 throughgear reduction 43. Suitable rotary unions 44 are provided upon each ofthe shafts for ingress and egress of a heat exchange fluid to each ofthe rotors, the fluid being admitted to the interior of a baflle tube 47provided within each shaft 18,, the fluid issuing through an outlet 49(Figure 1) at the top of each bafiie tube and then passing downwardlythrough the hollow center of the rotor and discharging via a rotaryunion 44. Fluid is also admitted to circulate through the hollow covers31 and in the space between tube 14 and each of the surrounding screwconveyor housing members 22. In this connection, it is to be noted thatall joints and welding that retain the heat exchange medium are locatedso that fluid circulating in the areas exterior to the housing for therotors cannot gain access through any joint and, further, all suchjoints are exposed so that any leak can be readily observed. Also, allfluid connections are beneath the casing as is the power equipment, thusensuring that any fluid or lubricant leaks cannot contaminate thematerial being processed.

At the top of the structure, a header, generally indicated at 51, isprovided, having down spouts 52 each leading to a passage 53 providedbetween an outer cover 31 and a rotor cover member 23. immediatelybeneath the header 51 is provided a distributing come. 54; this can bearranged with a gate portion, permitting by-pass of a desired quantityof the material entering header 51 into tube 14, if this is desired.Material at the bottom of tube 14 is taken off by a suitable conveyor(not shown) in passage 56.

In using this apparatus, the material is introduced through the header51 and unless by-passed, falls down through the several passages 53, thematerial entering between the screw pairs through an inlet 57 providedin the bottom of housing members 22 and 23. The material is movedupwardly by the helical rotors in rubbing contact with the heat exchangesurfaces provided by the housing members 22 and 23 and with the hollowshaft and helical fins of the rotors themselves, issuing from the top ofthe rotors and falling downwardly through the tube 14, to be removedthrough the outlet 56. If desired, one or more of gates 28 can be openedto permit of partial or complete recirculation.

it is obvious that with this feature of recirculation the processor canbe operated on a continuous, semi-continuous or batch cycle basis. Ifpart of the material is recirculated, by blending with other material,increased heat exchange is facilitated. If complete recirculation ispractical, the unit functions as a batch processor, retaining the batchfor the properv time to accomplish the full heat exchange desired, thenby closing the recirculating door the material can be discharged throughtube 14 to the discharge conveyor provided at 56.

The equipment described is particularly useful in the cooling or"cement. However, it is not limited to handling of only this material,since it can be used successfully upon salt, grain, flour, starches andthe like, and upon such diverse materials as meat scraps, tomatoes, babyfoods, and various slurries. The action of the screws is to move. thematerial with a scrubbing action over the heat exchange surfaces. Whendesired, as in the case of handling meat scrap, particle degradation canbe eniphasized by the clearances between the interfolded helices.Likewise when handling materials where particle degradation is desiredto be at a minimum, such as sugar, the clearances are increased.

The action of the screw conveyor flights is to spread the material overthe areaof the heat exchange surfaces, promote particle relocation andintimate contact. Thus, highly efiicient heat exchange is obtained. Therotors are turned at as slow a speed as is possible to secure upwardmovement of material. Also, the space between the rotors and the casing,the free space about the rotors, ispreferably filled with materials.Further, the rotors preferably fit the casing as snugly as possible tomaintain fall-back of material to a minimum.

In that form of the invention shown in Figures 3-6, I have illustrated asomewhat simpler form of apparatus. In this, a single pair of helicalrotors or screw conveyor flights 61 and 62 are mounted upon hollowshafts 63 and 64, the, latter being supported by bearings 66 and 67,provided at the top of a casing structure, generally indicated at 68;the lower ends of the shafts are supported by bearings 69 and 70. Thecasing structure 68 includes a down pipe 69 and a first arcuate housingmember fitting the interfolded screw conveyor flights; housing member 76is flanged at 71, as is an outer cover member 72. Mounted upon the outercover 72 is a shell 73, having a plurality of interior dividers 74 and'75 on each side thereof to provide a plurality of heat exchangepassages in conjunction with the screw conveyor cover member 72. Anouter shell. 76 is also provided about the pipe 69 and about a portionof screw conveyor housing member 70. Vertical dividers 77 are providedbetween the shell 76, pipe 69, and the screw conveyor housing member'70, to provide a plurality of passages for heat exchange fluid.

The screw conveyor flights are driven by suitable gearing 81 from aprime mover, not shown, which drives a sprocket 82 mounted upon shaft63. Heat exchange fluid is introduced through the rotary union '83mounted upon each, of the shafts.

Material to be processed is fed into the hopper 86 and is then moved bya horizontal screw conveyor flight 87 through casing 88 into inlet 89 ofcasing 63. The material is circulated through the equipment, beingreturned through the down pipe 69 to the feeder screw 87. When it isdesired to remove the material and empty the apparatus, the direction ofrotation of the feed screw is reversed, and the material is dischargedthrough the outlet pipe 92. If it is desired to operate the apparatuscontinuously, then down spout 69 can be so provided as to lead all or aportion of the material away.

In processing tallow and like material, a portion of the area of thecover member 72 is provided with a plurality of small holes, e.g., /3holes on A centers, so that the tallow will drain off of the meat scrapand so can be led away through passage 91, and moisture vapors may risethrough passage 91.

In a typical installation, the meat scrap is introduced in hogged formfrom a hog to the double helical rotors rotating intermeshed at 50r.p.m. These rotors are 9" in diameter and 20' high. The meat scrap,weighing about 60 pounds per cubic foot, will' be recirculated at therate of twenty-one tons per hour and this recirculation tends tohomogenize the product. Steam passing through the heat exchange ductsraises the temperature of the material, usually to about 216 F. Thiscauses a break-down of cells and a release of the tallow, which exudesthrough the perforated area of the cover 72 and falls to the bottom ofpassage 91, while the water vapor passes off through the top of saidpassage. This action of the screws is such that it keeps the small holesclean. As the meat scrap is reduced in volume, additional cold materialis added. When the tallow is completely rendered from the mass, theremaining cracklings are discharged, as herebefore described. Theapparatus shown is not only useful in treating materials such as tallowand other materials, but in the precrushing or scalping of wine grapes,in which stems, seeds and skins are separated from the juice.

From the foregoing, I believe it will be apparent that 1 have provided anovel, simple and improved form of heat exchange device, which will meetwith many diverse uses.

1 claim:

1. A device of the character described comprising a vertical tube havingan inlet at its upper end and an outlet at its lower end, a plurality ofpairs of interleaved screwconveyor flights extending parallel andclosely adjacent to said tube, a casing closely fitting each screw pair,means joining adjacent casings and the tube to provide heat exchangepassages, a cover on each casing providing a passage for material, meansfor introducing material into each passage, an inlet from each passageinto each casing at the lower end thereof, each screw pair discharginginto the inlet of said tube, each screw flight being mounted on a hollowshaft, and means for circulating a heat exchange fluid through eachshaft and through the heat exchange passages between the casings and thetube.

2. A device as in claim 1 wherein each casing includes an outer coverand an inner cover having outwardly extending sidewalls spaced apart adistance slightly greater than the width of the interleaved screws topermit removal of the screws upon removal of the outer cover.

References (Zited in the file of this patent UNITED STATES PATENTS1,155,190 Althoff Sept. 28, 1915 2,274,948 Ahlrnann Mar. 3, 19422,319,429 Nelson May 18, 1943 2,516,071 Pavia July 18, 1950 2,686,336Kleinlein Aug. 17, 1954 2,721,806 Oberg et al. Oct. 25, 1955 2,731,241Christian Jan. 17, 1956 2,745,856 Dayen et al May 15, 1956 2,753,159Christian July 3, 1956 FOREIGN PATENTS 112,802 Switzerland Feb. 13, 1925329,723 Great Britain May 29, 1930 438,007 Germany J an. 24, 1925815,103 Germany Sept. 27, 1951 877,326 Germany May 21, 1953 915,689Germany July 26, 1954

